Question

The product of two consecutive odd integers is 2,115. Find the integers. Which of the following quadratic equations could be used to solve the word problem?

a. x² + x - 2,115 = 0
b. x² + 2x - 2,115 = 0
c. x² + 2x + 2,115 = 0

Answer 1

x² + 2x - 2,115 = 0

Explanation:

Two consecutive odd integers looks like x+2. consecutive numbers are x+1. (odd numbers skip by 2 numbers. like between 5 and 7 is 2. )

SOOOO....

Now we can start. The product of two consecutive odd integers looks like

x(x+2) and it equals 2, 115 ---> x(x+2)=2,115

solve left side: x^2 +2x = 2,115

then move 2115 to left side to have a quadratic equation (make it equal to zero)

now we have:

x^2 +2x -2,115=0

that is you answer!

Hope it helps! ;)

Answer 2

Hello,

Answer B


Let x the first number
x+2 the second

x*(x+2)=2115
==>x²+2x-2115=0
==>x=45 or x=-47
==>(x=45 and x+2=47) or (x=47 and x+2=-45)